Talk:DSLAM

Maximum speeds?

I might be reading the article wrong, but it seems to suggest the maximum speed for ADSL to be 25mbit/s:

25 Mbit/s at 1,000 feet (~300 m)

so how come I have a 40mbit ADSL connection here?

82.161.50.114 (talk) 01:45, 18 March 2014 (UTC)

Pathway

The pathway of data listed here is confusing. A flowchart would be better.

 As a reader not too familiar with this field, this i really not too helpfu.  —Preceding unsigned comment added by Findingdan (talk • contribs) 19:30, 4 December 2009 (UTC) 

Central Office confused with Dslams

"Central Office must now collect all the different digital signals from its modems and combine them into a single signal, via multiplexing..."

The above statement is confusing. What modem? The Dslam collects all the Adsl modem signals and then multiplexis this data on a single Gigabit link usually fiber. Multiple Dslams are connected via Fiber at the Central Office,but the Central office itself has got nothing to do with Dslams?

dslams layer 2

how can DSLAMS be 'purely' layer 2 devices when DSL is a layer 1 application?

i want to tell u that u should describe the working of dslam separately so that it is easy for user to understand.

Diagram

Is it possible for someone to create a diagram of the part the DSLAM plays in DSL connections? DSL's section What Happens When You Use DSL and this article has numbered items, however I think a diagram showing the process will be easier to understand. Cheers, —TheJC (Talk • Contribs • Count) 10:26, 2 October 2006 (UTC)

Directionality

The section on "role of" seems to change direction in midstream. Paragraph one describes the upward flow of data, and paragraph three seems to be about a downward flow towards the customer, but no paragraph clearly indicates the shift in point of view.

Also the Main Distributing Frame seems out of sequence. Doesn't the upward flow encounter MDF before going through DSLAM? Jim.henderson 17:36, 18 October 2006 (UTC)

Attempt to clarify the confusing DSLAM article

A DSLAM is a Point-to-Multipoint device. It can be thought of as a massive Switch. It strength lies in it's ability to download/upload high bandwidth content to each ADSL modem, connected to it's ports, over twisted pair copper. DSLAM sizes vary between eight and 1000 ports. The eight port uses RJ-45 telephone jack connectors. The larger port sizes use a Telco-50 connector cable. Each port connects to only one ADSL modem.

Functioning as a switch, it receives the ADSL modem data (connected to it via twisted pair copper wire) on a port and streams this data via the Ethernet gigabit link that physically plugs into the DSLAM itself unto the Internet or local network.

The DSLAM can multicast a video stream to all the ADSL modems at the same time. An eight-port DSLAM can stream eight different movies and at the same time the ADSL modems can upload data unto the DSLAM to be routed unto the Internet or local network via the DSLAM's Gigabit Ethernet port. This allows for See http://en.wikipedia.org/wiki/Triple_play_%28telecommunications%29 The DSLAM has QOS and bandwidth control in increments of 32k, allowing bandwidth management to each ADSL modem.

DSLAM's often support rfc1483 to convert from Ethernet over ATM to Ethernet, since most DSL modems transport over rfc1483 for historical reasons.

Upload speed from an ADSL modem to it's DSLAM port: 1Mbps at a distance of 1.6km

Download speeds from a single DSLAM port to it's ADSL modem

• 25Mbps at 300m
• 24Mpbs at 600m
• 23Mpbs at 900m
• 22Mpbs at 1200m
• 21Mpbs at 1500m
• 19Mpbs at 1800m
• 16Mpbs at 2100m

(did not bother to convert properly) As the distance of the ADSL modem from the DSLAM increases the throughput will drop. At any distance where the speed becomes unacceptable , connect a Fiber/Ethernet module to the ADSL modem's ethernet port. The ADSL modem could be seen as an ATM to Ethernet protocol converter. All switches, hubs, routers and bridges uses the Ethernet protocol. —Preceding unsigned comment added by 196.11.241.194 (talk • contribs) 13:58, 20 October 2006

Clarify "Path Taken" section

Oof, I hope my rearrangement and addition made more clarity than additional buttiness. Problem is, it has now become an even worse fit with the following "Role of" section, which needs its subscriber wire information trimmed and its ISP information beefed up.

The Talk page information on ADSL download speed will be useful when it goes into ADSL, not DSLAM, but the comment on protocol conversion should be carefully integrated into DSLAM. The material on stateful firewall, contention, and other optional or advanced concepts belongs at the end of the article, not the begining. Much heavy lifting to do yet before this becomes a candidate for Featured Article. Jim.henderson 04:13, 25 October 2006 (UTC)

All right; I moved a lot of the hardware and feature details out of the preample and to the end, which is still a bit of a jumble. Some of that material belongs in the "Role of" paragraph, which I trimmed drastically since it repeated in less clear form what was already in "Path taken". It could easily have been misinterpreted as indicating that the usual data path did not go through Internet. I added most of a paragraph to the preamble to clarify the relation of DSLAM to CO. Maybe the preamble should still be trimmed a little. That's enough for now; I'll check again in a few hours to see whether anyone else has made some improvements. Jim.henderson 14:55, 25 October 2006 (UTC)

It's a multiplexer

Its impossible to give an accurate description of a DSLAM without full reference to the whole point of having

a DSLAM: Streaming high bandwidth data from a single point to multiple points and receiving data from multiple points in order to Multiplex these ADSL modem data unto the Telco backbone.

Right. Too much detail is still front loaded in the preamble, which should concentrate more on the point that it's a multiplexer. Of course, one may also say the whole point to having a DSLAM is to use old telephone wires for new services. Both points should be mentioned in the preamble while most other ideas belong in the "Role of" section. Incidentally, the term "high bandwidth data" is misleading for the Megabits per Second copper end of a DSLAM, since that's the slow end. The fast end is Gigabits on glass. "Streaming" and "backbone" are jargon, and should be defined in the article if they cannot be avoided. Jim.henderson 13:34, 26 October 2006 (UTC)

Dslam is a switch and router combination

Digital subscriber line access multiplexer can also rephrased as: ADSL modems router The word 'Multiplex' slightly obscures the fact that the Ethernet Gigabit upload port at the back of the dslam Routes the ADSL modems connected to its ATM protocol ports(switch) over any network via the Ethernet protocol. So a Dslam should be visualized as a massive switch connected to a Router. The stuff about the CO,Telephone firms confuses this. A Dslam is merely a device used by telcos to build a telephone exchange. A more accurate description is to view a Dslam as forming a huge LAN. These large DSLAM LANs link into a WAN and viewing a Telephone company as a WAN operator. In the intro of the article zero reference should be made to Telephone exchanges or companies or telco because a Dslam just like a Router, Hub, Bridge and Switch has got nothing to do with Telcos.

A Router connected to a Switch can also be described as 'multiplexing' the Switch's data via it'sGigabit Ethernet port unto a network.As far as a Router and Dslam is concerned their Gigabit Ethernet ports 'multiplexes' or 'routes' their data via the Ethernet protocol unto a computer network that also uses the Ethernet protocol. This has got nothing to do with Telco backbones, http://en.wikipedia.org/wiki/Serving_Area_Interface and http://en.wikipedia.org/wiki/Digital_loop_carrier. Backbones and SAI can also be formed using Ethernet based Routers and Switches but because of the distance limitation of 100m over copper with Ethernet, Telcos use Dslams.

Thus a Dslam is an ATM protocol based switch. Where a 'normal' switch is an Ethernet based switch. A Dslam ATM port interfaces via an ADSL modem to an Ethernet device, where a switch interfaces directly via the Ethernet protocol to an Ethernet device. Upto eight Dslams can be daisy chained. I am not sure about this but I believe Dslam1 connects via one of it's ATM ports to Dslams2's ATM port. These two Dslams then communicate via the ATM protocol.

The word subscriber confuses the role of a DSLAM even further. Human beings subscribe to a certain world view. A DSLAM and a network switch are not subscribing to anything, they are interfacing via a communications protocol either Ethernet or ATM to another device using the same protocol

Excellent. Well, before getting to the good part, let's have some moaning and carping. Editors shouldn't be anonymous; we should use four tildes to sign our work with our Wiki account so we can look in each others personal page and other works and see what our colleague is about. My personal discussion page for example says I'm an antique telephone worker, which will give a clue to my POV on many issues. More moaning: here I worked long and hard to clear up a vastly confusing article and now along comes a bright newcomer who doesn't appreciate my terrible sacrifices, boo-hoo. Yeah, it's a little silly of me, but moaning can be fun.

Another bit of carping: Eh? You propose to leave out the "S" from DSL and DSLAM? And the "M"? But, subscribers are what it's about. They're the ones paying for it all. They want something, namely Internet access, and the phone companies have something, namely phone wires. DSLAM makes the resource fit a new need, and the "M" part lets the old wires continue to do their old job. CATV and FIOS don't use DSLAM, because they don't use old telephone wires. That's why subscribers and telcos both belong in the preamble. Maybe the preamble (or "lead" in Wiki jargon) can be shaved a little more, but don't lose sight of the people at both ends of the wire. At the remote end of the wire you've got consumers who call up the phone company and pay for Internet service.

All right, finally to the constructive part. Yes, DSLAM creates a large LAN, wider than Ethernet can provide. That's the missing insight. Ethernet can't reach out for Kilometers because it doesn't take full advantage of the abilities of twisted pairs but DSLAM is made to wring every "bit" of performance out of old telephone wires. Thus its LAN can reach out and touch subscribers far from the telco central office, as pointed out in the table of distance vs speed. Do you propose to write a new section on "DSLAM as LAN," or to rewrite the currently murky "Role of DSLAM" section so it makes this point more clearly? Either could greatly improve the article. As it stands today, the article perhaps says too much about DSLAM as telephone equipment. Certainly it says too little, or says it too vaguely, about DSLAM as LAN equipment.

Jim.henderson 20:42, 2 November 2006 (UTC)

This is obviously wrong: "A DSLAM may offer the ability to tag VLAN traffic as it passes from the subscribers to upstream routers." VLANS are specific to Ethernet, while ATM uses virtual circuits.

Some comments here need some clarification as well: "Ethernet can't reach out for Kilometers". It can, it just can't over copper. And it can't work over 2-wire TP at all. BUT: the newer VDSL technology uses Ethernet Frames (the layer-2 part of ethernet) instead of ATM cells as ADSL does.

Capital style

This article has no capital letters in its name, while Asymmetric Digital Subscriber Line capitalizes every word. Is one style right, and the other wrong? Jim.henderson 02:37, 22 March 2007 (UTC)

DSLAM article is a trainwreck

The article confuses Telco jargon terms with function and role of a DSLAM. This http://scratchpad.wikia.com/wiki/DsLam link is how the article should be written. Role of the DSLAM:
"...The DSLAM, functioning as a switch, collects the ADSL modem data (connected to it via twisted or non-twisted pair copper wire) and multiplexes this data via the gigabit link that physically plugs into the DSLAM itself, into the Telco's backbone." No, the Gigabit ethernet port on the DSLAM doesn't interface with a "backbone", it interfaces with an Ethernet based device such as a PC. The PC in turn would configure the DSLAM to say for example allocate each ADSL modem with 32k bandwidth. Telco's use DSLAMs, but this has got nothing to do with the DSLAM as a switch/router device itself. —Preceding unsigned comment added by 41.242.230.126 (talk • contribs) 18:35, 1 May 2007 (UTC)

single line IP-DSLAMs

Are there any cheap simple single line IP-DSLAMs for use as long-range ethernet extenders?-96.237.78.13 (talk) 19:41, 18 August 2010 (UTC)

Yes - and no. There are VDSL2-based ethernet extenders on the market (e.g. from Allied Telesis and LevelOne), but being single line they cannot be called multiplexers or DSLAMs. Opvind (talk) 19:37, 3 August 2011 (UTC)

mmm

mm m. — Preceding unsigned comment added by 182.185.241.144 (talk) 12:40, 16 March 2012 (UTC)

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Jargon in the Lede section

What is a "high-speed digital communications channel?"

The assumptions that spawned that term in an intro section may be why the lede does not meet wiki guidelines RE: "general user." See: MOS:LEAD And:

http://en.wikipedia.org/wiki/Wikipedia:Make_technical_articles_understandable
"WP:Jargon" redirects here.   "This page in a nutshell: Strive to make each part of every article as understandable as possible to the widest audience of readers who are likely to be interested in that material."   That page also says: "The general reader has no advanced education in the topic's field, is largely unfamiliar with the topic itself, and may even be unsure what the topic is before reading."

Like me. I came here find out what the topic is. Like how does it differ from a server? Do ISPs use them? What are they not? Examples? Those are some normal explanatory (communication) concepts worthy of consideration.

Also consider, a list of facts is NOT an explanation.
— Preceding unsigned comment added by 2602:306:CFCE:1EE0:5DF8:B150:A31E:43B8 (talk) 19:54, 16 April 2019 (UTC)

Requested move 11 June 2023

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion.

The result of the move request was: moved. (closed by non-admin page mover) CLYDE ^{TALK TO ME}/_{STUFF DONE} (please mention me on reply) 01:28, 19 June 2023 (UTC)

---

Digital subscriber line access multiplexer → DSLAM – Per WP:COMMONNAME and MOS:ACROTITLE. The acronym is more commonly used than the full name and the acronym is only used for this subject. PhotographyEdits (talk) 19:35, 11 June 2023 (UTC)

• Support - having worked in telecom, DSLAM (dee slam) is the common usage and the only time I ever heard digital subscriber line access multiplexer used was as an answer to the question "What does DSLAM stand for?" -- Whpq (talk) 20:18, 18 June 2023 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.